Should I hear my bypass right before shifts?

I think the sound I am hearing is from my Bosch bypass valve but I thought it was only supposed to relieve pressure when you let off the throttle. The noise I am hearing sounds like a really fast pulse or a whoosh of air. Its coming from the corner under my hood where my bypass valve is so that is what I'm assuming the noise is.
Anyway, I am hearing this right before my car shifts, seemingly as the rpm's are still rising. I have an AOD by the way. But does the bypass valve see the tranny shift as a "letting out of the gas" or a lessening of load and start to open just prior to a shift? Or is something else going on here. Thanks for any info, Ryan

if you have it hooked properly it should only open when you let off the gas....as long as the vac. line has boost there is no way it should open

You'll hear it as soon as the car sees vacuum.

Well good news.... it wasnt my bypass it was my belt slipping. Having never heard belt slip before I didnt know what I was hearing. Unfortunately this wasnt suggested to me as a culprit until right when the track closed today so I didnt get time to tighten the belt and make another pass. But when I got home I tightened it up and went for a spin real quick and sure as hell no more noise and more boost! :) Now I cant wait to get back to the track and with some stickier tires. She went 12.0 @ 116 mph today on 17" street wheels and some DR's. My best 60ft was 1.9 so there is much improvement. So I hoping for mid 11's with some ET Streets on my Weld wheels next time out. Thanks again for the good info fellas, Ryan

Hey Ryan,
What type of work did you do on your AOD? Is it a stock AOD with a different valve body?

Thanks,
Troy

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Originally Posted by NothinButNotch

Well good news.... it wasnt my bypass it was my belt slipping. Having never heard belt slip before I didnt know what I was hearing. Unfortunately this wasnt suggested to me as a culprit until right when the track closed today so I didnt get time to tighten the belt and make another pass. But when I got home I tightened it up and went for a spin real quick and sure as hell no more noise and more boost! :) Now I cant wait to get back to the track and with some stickier tires. She went 12.0 @ 116 mph today on 17" street wheels and some DR's. My best 60ft was 1.9 so there is much improvement. So I hoping for mid 11's with some ET Streets on my Weld wheels next time out. Thanks again for the good info fellas, Ryan

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Troy,

I actually didnt have any of it done. The buddy I bought the notchback body from actually sold me the tranny with it for really cheap so I took it (and have actually enjoyed it more than I thought I would). However, I know it does have a hardened input shaft, a different valvebody, a B&M shift kit, a cooler up front, and a higher stall (2600-2800). It is suppose to hold up to 600 HP and knock on wood so far has done just fine for me. I wouldnt mind having a touch higher stall, like a 3000-3200, but probably wont change it unless something goes wrong. I do plan to put in a fully manual Lentech valvebody though sometime in the near future.

Sorry I cant provide you with any specifics but thats the info I have, Ryan